Multiple if condition in Matlab

I have a problem regarding the statements below. When I run the code it doesn't go into the needed condition and doesn't make the transformations that it should. Any error that I can not spot? Thanks in advance.

clear all;
clc;
recenica=('STEFI');
i=1;
dolzina = length(recenica)

while i<=length(dolzina)
prva=recenica(i);
vtora=recenica(i+1);


if recenica(i)==('P' | 'M' | ' ')
    prva='B';
end
if recenica(i)==('U')
    prva='O';
end
if recenica(i)==('V')
    prva='F';
end

if recenica(i)==('G' | 'X' | 'Y' | 'J' | 'I')
    prva='K';
end

if recenica(i)==('L' | 'T' | 'D' | '3' | '2')
    prva='N';
end

if recenica(i)==('Z' | '1' | 'C')
    prva='S';
end

if recenica(i)==('5' | 'Q' | '4')
    prva='6';
end

if recenica(i)==('R')
    prva='H';
end


if recenica(i+1)==('P' | 'M' | ' ')
    vtora='B';
end
if recenica(i+1)==('U')
    vtora='O';
end
if recenica(i+1)==('V')
    vtora='F';
end

if recenica(i+1)==('G' | 'X' | 'Y' | 'J' | 'I')
    vtora='K';
end

if recenica(i+1)==('L' | 'T' | 'D' | '3' | '2')
    vtora='N';
end

if recenica(i+1)==('Z' | '1' | 'C')
    vtora='S';
end

if recenica(i+1)==('5' | 'Q' | '4')
    vtora='6';
end

if recenica(i+1)==('R')
    vtora='H';
end


a=strcat(prva,'.jpg');
b=strcat(vtora,'.jpg');

generiranje=Test3(a,b);
i=i+1;
end